T-Mobile USA does this. Based on your credit score (and from my understanding their policy is very liberal) they give you an interest-free loan to get a more expensive phone. Your payments are spread out over the first six or so monthly bills.

Of course, the reason they do this is obvious; they want to sell you the most expensive phone they can. I'm very careful with my credit so I declined that offer back when I first joined T-Mobile, and opted to buy a lesser phone with the cash I had on hand. I didn't regret it as I was very satisfied with the phone (BB Curve 8520).